CareerCup

/* align_size has to be a power of two !! */
void *aligned_malloc(size_t size, size_t align_size) 
{
	char *ptr,*ptr2,*aligned_ptr;
	unsigned int align_mask = (unsigned int)align_size - 1;

	/* We need to use malloc provided by C. First we need to allocate memory
	of size bytes + alignment + sizeof(void *). We need 'bytes' because 
	user requested it. We need to add 'alignment' because malloc can give us 
	any address and we need to find multiple of 'alignment', so at maximum multiple
	of alignment will be 'alignment' bytes away from any location. We need 
	'sizeof(void *)' for implementing 'aligned_free', since we are returning modified 
	memory pointer, not given by malloc ,to the user, we must free the memory 
	allocated by malloc not anything else. So I am storing address given by malloc just above 
	pointer returning to user. Thats why I need extra space to store that address. 
	Then I am checking for error returned by malloc, if it returns NULL then 
	aligned_malloc will fail and return NULL.
	*/

	ptr = (char *)malloc(size + align_size + sizeof(void *));
	if(ptr == NULL) return(NULL);

	ptr2 = ptr + sizeof(void *);
	aligned_ptr = ptr2 + (align_size - ((unsigned int)ptr2 & align_mask));
	
	ptr2 = aligned_ptr - sizeof(void *);
	*((int *)ptr2)=(int)(ptr);

	return(aligned_ptr);
}


void aligned_free(void *ptr) 
{
	int *ptr2=(int *)ptr - 1;
	ptr = (*ptr2);
	free(ptr);
}

void *align_mem_alloc(size_t size, size_t alignment){
	void *pa, *ptr;
	pa=malloc(sizeof(size)+sizeof(void *)+sizeof(alignment-1));
	if(!pa)
		return NULL;
	ptr=(void*)(((size_t)pa+sizeof(void*)+alignment-1)&(~(alignment-1)));
	*((void**)ptr)=pa;
	return ptr;

}

void align_free(void *ptr){
	if(!ptr)
		return;
	free(*((void**)ptr-1));

}

sizeof(size)+

any improvement on this?